Hexosaminidase A and Total Hexosaminidase, Leukocytes
Use
Used for diagnosis and carrier testing of Tay‑Sachs disease (deficiency of Hexosaminidase A due to HEXA gene variants) and Sandhoff disease (deficiency of both Hexosaminidase A and B due to HEXB gene variants) in leukocytes. Differentiates between these lysosomal storage disorders via enzyme activity levels in white blood cells. Follow‑up molecular testing may be indicated for clarification of pseudodeficiency alleles or confirmation. Appropriate for males and pregnant or nonpregnant females.
Special Instructions
Specimen must be collected in ACD (yellow‑top) tube and arrive within specified stability window; draw Monday through Thursday only (not before a holiday). New York state clients require documentation of informed consent as indicated on the requisition or electronic order. Testing is performed one or two days per week (semi‑automated heat inactivation fluorometric method).
Limitations
Specimen cannot be frozen; gross hemolysis may lead to rejection. The assay may not detect rare variants or carrier states accurately without follow‑up molecular testing. Not FDA approved; performance characteristics established under CLIA. Pediatric reference ranges differ by age group.
Methodology
Immunoassay (Multiplex Protein Panel)
Biomarkers
LOINC Codes
- 87544-3
- 24075-4
- 23825-3
- 59462-2
- 18771-6
Result Turnaround Time
2-6 days
Related Documents
For more information, please review the documents below
Specimen
Whole Blood
Volume
6 mL
Minimum Volume
5 mL
Container
ACD (yellow‑top) tube
Collection Instructions
Draw blood in ACD Solution A or B yellow‑top tube; send 6 mL refrigerated, with cold packs; keep cool, do not freeze; draw Monday through Thursday only and not the day before a holiday; package as close to shipping time as possible.
Storage Instructions
Refrigerated (preferred), ambient acceptable; do not freeze
Causes for Rejection
Gross hemolysis
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 4 days |
| Refrigerated | 4 days |
| Frozen | Unacceptable |